Benford's Law for Quality Assurance of Manner of Death Counts in Small and Large Databases.

To assess if Benford's law, a mathematical law used for quality assurance in accounting, can be applied as a quality assurance measure for the manner of death determination. We examined a regional forensic pathology service's monthly manner of death counts (N = 2352) from 2011 to 2013, and provincial monthly and weekly death counts from 2009 to 2013 (N = 81,831). We tested whether each dataset's leading digit followed Benford's law via the chi-square test. For each database, we assessed whether number 1 was the most common leading digit. The manner of death counts first digit followed Benford's law in all the three datasets. Two of the three datasets had 1 as the most frequent leading digit. The manner of death data in this study showed qualities consistent with Benford's law. The law has potential as a quality assurance metric in the manner of death determination for both small and large databases.

Odds ratios deconstructed: A new way to understand and explain odds ratios as conditional risk ratios.

OBJECTIVES: The aim of this analysis was to provide an alternative derivation of the odds ratio (OR) to provide an intuitive meaning, freeing it from any mention of odds, which may make it a more useful concept for clinicians to use when describing treatment effect. STUDY DESIGN AND SETTING: By examining the four possible combinations of treatment/control and corresponding outcomes, we considered the conditional risk ratio (RR, also known as relative risk) of an event with the treatment compared with an event with the control for pairs of patients for whom treatment and control would yield different results. Both matched and unmatched studies are considered. RESULTS: We found that the OR could be derived as the RR of an outcome with treatment compared with an outcome with control conditional on the treatment and control resulting in different outcomes, thus providing a measure of the net benefit of treatment. CONCLUSION: It has been claimed that the OR comparing the effect of treatment vs. control does not have the same clinical interpretability as RR because it involves ratios of odds and so is difficult to explain in terms of patient numbers. This new derivation provides an interpretation of the OR as an RR but conditional on treatment and control resulting in different outcomes. This may help explain the reason ORs cause interpretation difficulties in practice. Moreover, the OR may be a more clinically useful parameter to patients because it deals with only those situations where the outcome differs between the two groups.

The use of video before arthroscopic shoulder surgery to enhance patient recall and satisfaction: a randomized-controlled study.

BACKGROUND: Historically, the preoperative consultation has consisted of a discussion between patient and surgeon. There is a growing literature describing efforts to integrate multimedia into surgical patient education. This study aimed to assess the efficacy of an educational video tutorial on early learning of information specific to patients undergoing shoulder arthroscopy when it was used as an adjunct to the standard preoperative consultation. METHODS: This study was a surgeon-blinded, randomized controlled trial involving 40 consecutive patients requiring shoulder arthroscopy. After a preoperative consultation with an orthopaedic surgeon, patients were randomized in a 1:1 ratio to either a control group or a treatment group. The treatment group viewed a 10-minute video, which covered the expected preoperative, intraoperative, and postoperative experience. Immediately afterward, both groups completed a questionnaire measuring satisfaction and recall of information received. All patients completed a second questionnaire at the first postoperative visit that assessed overall satisfaction with their experience. RESULTS: Thirty-four patients were available for follow-up. The video group (N = 15) answered 87% of the knowledge questions correctly, whereas the control group (N = 19) answered only 56% (P = .000). There was stronger agreement in the video group that the preoperative consultation contained an appropriate amount of information (P = .039). Postoperatively, there was agreement that the video was an effective preparation tool for all stages of the surgical experience. However, there was no difference between the groups in satisfaction with their overall surgical experience. CONCLUSIONS: Video can enhance patients' operative experiences and improve their retained knowledge when it is used as an adjunct to the preoperative consultation. LEVEL OF EVIDENCE: Basic science, education methodology study, devices to improve learning.

Faà di Bruno's formula and the distributions of random partitions in population genetics and physics.

We show that the formula of Faà di Bruno for the derivative of a composite function gives, in special cases, the sampling distributions in population genetics that are due to Ewens and to Pitman. The composite function is the same in each case. Other sampling distributions also arise in this way, such as those arising from Dirichlet, multivariate hypergeometric, and multinomial models, special cases of which correspond to Bose-Einstein, Fermi-Dirac, and Maxwell-Boltzmann distributions in physics. Connections are made to compound sampling models.